How about one-comment.com for reducing the clutter from HN comments thread?

KandanApp , the best opensource alternative for HipChat https://github.com/kandanapp/kandan

in the settings, you can change the color of HN topbar

why HN don't provide this functionality as part of the site?

You mean besides the "Search" box at the bottom of every page?

Suggest solution to help japan with it's nuclear disaster

by beatiful, I meant an algorithm that it is simple, easy to understand and still has an intelligent solution. I'm not sure that algorithm in computiational fluid dynamics feat...

Those terms, simple and easy, should be taken as relative to the system being described.

I would argue that CFD models are surprisingly simple relative to the task of understanding multi-phase, particle-laden, turbulent fluids.